The canals of Amsterdam have been winding their way through the city for 800 years. Construction of a new metro line made it necessary to clean them out, and an amazing variety of items have been dredged up from the bottom. Those items have been collected, analyzed, sorted, and put on display in a digital archaeological database.

The associated website, book and documentary set titled Below the Surface has been years in the making. This project catalogues everything from bits of ceramic, metal and glass to fully intact artifacts. Some finds predate the city’s founding — there are medieval coins and even pieces of sharpened stone from as far back as 4,300 BCE.

“Rivers in cities are unlikely archaeological sites,” explain the organizers and curators of the project. “It is not often that a riverbed, let alone one in the middle of a city, is pumped dry and can be systematically examined. The excavations in the Amstel yielded a deluge of finds.” The resulting website is an amazing interactive museum, allowing visitors to dynamically connect various artifacts by type, material and time period.